Fallopian tube abnormalities in uterine serous carcinoma

Clinical outcomes following identification of an incidental p53 signature in the fallopian tube

Fallopian tube pathology in patients with BRCA1 and BRCA2 mutations suggests a possible pathway to high grade serous ovarian carcinoma originates with a p53 signature, which is thought to represent a potential precursor to serous tubal intraepithelial carcinoma (STIC). The clinical implications of an isolated p53 signature in the average-risk population has not been well-established. This study aims to describe clinical outcomes in patients with incidentally noted p53 signature lesions. All patients diagnosed with a p53 signature lesion on final pathology from 2014 to 2022 were identified at a large academic institution. P53 signature is defined by our lab as morphologically normal to mildly atypical tubal epithelium with focal p53 over-expression on immunohistochemistry. Incidental p53 signature was defined as identification of a fallopian tube lesion excised for benign or unrelated indications in patients without a known hereditary disposition. Demographic, clinicopathologic, and genetic data were collected. A total of 127 patients with p53 signatures were identified. Thirty-six patients were excluded for established ovarian cancer or high-risk history leaving 91 total patients. Five patients (5.5%) developed a malignancy, none of which were ovarian or primary peritoneal, at the end of the eight and a half year follow up period. Twenty-four (26.4%) patients had salpingectomy without any form of oophorectomy at the time of initial surgery, while 67 (73.6%) patients had at least a unilateral oophorectomy at the time of their salpingectomy. Seven patients (7.7%) had additional surgery after p53 signature diagnosis; however, the final pathology yielded no evidence of malignancy in all these patients. After subsequent surgeries, 19 (20.9%) patients maintained their ovaries. The diagnosis of an incidental p53 signature was not associated with any primary peritoneal or ovarian cancer diagnoses during our follow up, and the majority of patients were managed conservatively by their providers with no further intervention after diagnosis.

MYC is sufficient to generate mid-life high-grade serous ovarian and uterine serous carcinomas in a p53-R270H mouse model

Genetically engineered mouse models (GEMM) have fundamentally changed how ovarian cancer etiology, early detection, and treatment is understood. However, previous GEMMs of high-grade serous ovarian cancer (HGSOC) have had to utilize genetics rarely or never found in human HGSOC to yield ovarian cancer within the lifespan of a mouse. MYC, an oncogene, is amongst the most amplified genes in HGSOC, but it has not previously been utilized to drive HGSOC GEMMs. We coupled Myc and dominant negative mutant p53-R270H with a fallopian tube epithelium-specific promoter Ovgp1 to generate a new GEMM of HGSOC. Female mice developed lethal cancer at an average of 15.1 months. Histopathological examination of mice revealed HGSOC characteristics including nuclear p53 and nuclear MYC in clusters of cells within the fallopian tube epithelium and ovarian surface epithelium. Unexpectedly, nuclear p53 and MYC clustered cell expression was also identified in the uterine luminal epithelium, possibly from intraepithelial metastasis from the fallopian tube epithelium (FTE). Extracted tumor cells exhibited strong loss of heterozygosity at the p53 locus, leaving the mutant allele. Copy number alterations in these cancer cells were prevalent, disrupting a large fraction of genes. Transcriptome profiles most closely matched human HGSOC and serous endometrial cancer. Taken together, these results demonstrate the Myc and Trp53-R270H transgene was able to recapitulate many phenotypic hallmarks of HGSOC through the utilization of strictly human-mimetic genetic hallmarks of HGSOC. This new mouse model enables further exploration of ovarian cancer pathogenesis, particularly in the 50% of HGSOC which lack homology directed repair mutations. Histological and transcriptomic findings are consistent with the hypothesis that uterine serous cancer may originate from the fallopian tube epithelium.

Preoperative CA125 Significantly Improves Risk Stratification in High-Grade Endometrial Cancer

Patients with high-grade endometrial carcinoma (EC) have an increased risk of tumor spread and lymph node metastasis (LNM). Preoperative imaging and CA125 can be used in work-up. As data on cancer antigen 125 (CA125) in high-grade EC are limited, we aimed to study primarily the predictive value of CA125, and secondarily the contributive value of computed tomography (CT) for advanced stage and LNM. Patients with high-grade EC (n = 333) and available preoperative CA125 were included retrospectively. The association of CA125 and CT findings with LNM was analyzed by logistic regression. Elevated CA125 ((>35 U/mL), (35.2% (68/193)) was significantly associated with stage III-IV disease (60.3% (41/68)) compared with normal CA125 (20.8% (26/125), [p < 0.001]), and with reduced disease-specific-(DSS) (p < 0.001) and overall survival (OS) (p < 0.001). The overall accuracy of predicting LNM by CT resulted in an area under the curve (AUC) of 0.623 (p < 0.001) independent of CA125. Stratification by CA125 resulted in an AUC of 0.484 (normal), and 0.660 (elevated). In multivariate analysis elevated CA125, non-endometrioid histology, pathological deep myometrial invasion ≥50%, and cervical involvement were significant predictors of LNM, whereas suspected LNM on CT was not. This shows that elevated CA125 is a relevant independent predictor of advanced stage and outcome specifically in high-grade EC.

The Many Faces of Serous Neoplasms and Related Lesions of the Female Pelvis: A Review

Ovarian serous tumors and related lesions are one of the most common conditions of the female genital tract. While ovarian high-grade serous carcinoma carries high mortality and adverse prognosis, most other serous lesions have better clinical behavior. In recent years, significant progress has been made in understanding the nature and histogenesis of these lesions that has contributed to better and more precise clinical management. Most of the high-grade serous carcinomas involve the ovaries and/or peritoneum, although in most cases, their origin seems to be in the fallopian tube. This view is supported by the recognition of precursor lesions in the fallopian tube, such as p53 signature and serous tubular in situ carcinoma. This paper presents salient morphologic, immunohistochemical, and molecular data related to serous tumors and related lesions of the female pelvis and discusses the histogenetic interrelationship among these lesions in light of current knowledge.

The Origin of Ovarian Cancer Species and Precancerous Landscape

Unlike other human cancers, in which all primary tumors arise de novo, ovarian epithelial cancers are primarily imported from either endometrial or fallopian tube epithelium. The prevailing paradigm in the genesis of high-grade serous carcinoma (HGSC), the most common ovarian cancer, posits to its development in fallopian tubes through stepwise tumor progression. Recent progress has been made not only in gathering terabytes of omics data but also in detailing the histologic-molecular correlations required for looking into, and making sense of, the tissue origin of HGSC. This emerging paradigm is changing many facets of ovarian cancer research and routine gynecology practice. The precancerous landscape in fallopian tubes contains multiple concurrent precursor lesions, including serous tubal intraepithelial carcinoma (STIC), with genetic heterogeneity providing a platform for HGSC evolution. Mathematical models imply that a prolonged time (decades) elapses from the development of a TP53 mutation, the earliest known molecular alteration, to an STIC, followed by a shorter span (6 years) for progression to an HGSC. Genetic predisposition accelerates the trajectory. This timeline may allow for the early diagnosis of HGSC and STIC, followed by intent-to-cure surgery. This review discusses the recent advances in this tubal paradigm and its biological and clinical implications, alongside the promise and challenge of studying STIC and other precancerous lesions of HGSC.